/*
 * Copyright (c) 2007, Esko Luontola. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 *     * Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright notice,
 *       this list of conditions and the following disclaimer in the documentation
 *       and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package net.orfjackal.darkstar.integration.util;


import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Executes a shell command. Prints the output of the command.
 *
 * @author Esko Luontola
 * @since 1.12.2007
 */
public class ProcessExecutorImpl implements ProcessExecutor {

    public Process exec(String... command) {
        return exec(command, System.out, System.err);
    }

    public Process exec(String[] command, OutputStream stdout, OutputStream stderr) {
        try {
            Process process = Runtime.getRuntime().exec(command);
            redirect(process.getInputStream(), stdout);
            redirect(process.getErrorStream(), stderr);
            return process;

        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private static void redirect(final InputStream from, final OutputStream to) {
        Thread t = new Thread() {
            public void run() {
                byte[] buf = new byte[1024];
                int len;
                try {
                    while ((len = from.read(buf)) > 0) {
                        to.write(buf, 0, len);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        };
        t.setDaemon(true);
        t.start();
    }
}
